Current studies have shown that snowshoe hares are susceptible to infection by snowshoe hare virus, butare much less susceptible to infection by LaCrosse and Trivitattus viruses. Interferon appears at about the same time as viremia, but has been a difficult parameter to measure for technical reasons. In the coming year we intend to 1) determine the feasibility of using blood steroid levels as an objective measure of stress, 2) determine the effects of fluctuating warm temperatures on the host response (viremia and antibody) in hares infected with western equine encephalitis virus and 3) measure these same parameters for well nourished and undernourished hares maintained on winter browse and infected with WEE virus.